FR2713963A1 - Joining and welding installation using a laser beam of two coils of metal strips to form a continuous metal strip. - Google Patents

Abstract

The subject of the invention is an installation for splicing and welding by means of a laser beam (11) of two coils (1, 2) of metal strips, characterized in that it comprises unwinding means (3) and winding (9) of the reels (1, 2), an accumulator system (7) of the tape of the first reel (1), means (4) for detecting the tail (1a) of the first reel (1) ) and the head (2a) of the second reel (2), means (5) for shearing the tail (1a) of the first reel (1) and the head (2a) of the second reel (2) , means (6a, 6b) for guiding and supporting metal strips, an assembly (10) for positioning and holding the edges to be welded of the tail (1a) of the first coil (1) and of the head ( 2a) of the second coil (2) against each other and in the axis of the laser beam (11) and a laser beam welding assembly movable along the joint plane formed by the edges to be welded of said coils.

Description

The subject of the present invention is an installation for splicing and

  welding with a laser beam of two coils of metal strips for

  form a continuous metal strip.

  In steel processes, it is known, after having cold-rolled strips from a hot train to reduce the thickness, to make

  undergo these cold-rolled strips post-treatment

  rolling such as for example a homogenization annealing

  or stripping or coating.

  For this, the treatments being carried out continuously on scrolling, it is necessary for the sake of productivity to unwind the reels of bands and to re-join said bands one behind the other

in order to get a continuous strip.

  For this purpose, the tail of a first coil and the head of a second coil to be butted on the first are placed in overlap, each strip is flanged on either side of the interface in overlap and the interface overlapping by passage under stress of conductive knobs between which a

electric welding current.

  During this operation, the tail of the first strip stops scrolling towards the installation of

downstream processing.

  This operation is made possible without stopping the running of the strip in the treatment installation by interposition between said installation.

  welding treatment and installation, an accumu-

  strip reader which empties during the stopping of the tail of the first reel and fills as soon as the joining operation is completed and the strip of the second

reel advances.

  The problem of splicing the strips mainly lies in the fact that the welding operation results in local annealing and an excess thickness of the strip.

  at the overlap interface.

  This annealing results in a recrystallized structure.

edge of the welded area.

  However, the strips being initially cold rolled, they are strongly hardened with a structure

  lamellar oriented in the rolling direction.

  The metallographic structure of the continuous strip resulting from the splicing of two coils is therefore heterogeneous, a small annealed and recrystallized zone

  being surrounded by two strongly hardened zones.

  Thus, a characteristic profile follows.

  heterogeneous mechanical properties, the elastic limit and the breaking load being greater in the welded area than in the rest of the strip and, by way of

  as a result, a drop in hardness in the welded area.

  As a result, when one pulls on such a strip during the treatment which one wishes to subject him to, one very often attends a clear break in the

  level of the junction between the two zones.

  To avoid this type of problem, it is necessary to carry out a homogenization annealing of the

strip before welding.

  However, this type of annealing is not necessarily desirable in particular if one wishes to preserve the

hardened structure of the strip.

  In addition to these metallurgical problems, the welded zone has an extra thickness of the order of

  at 50% compared to the initial thickness of the strips.

  This extra thickness proves to be detrimental during the winding of the continuous strip, because at the time of the formation of the turns, due to the extra thickness of the solder, the coil has a defect in circularity which causes the strip leading to it to be marked. discarded. To minimize this effect of marking the strip, it is known to have, after the wheels of the welding installation, in line with the covering interface, a forging roller to crush the weld shortly after its formation when the metal is

still malleable.

  This transverse burnishing operation makes it possible to distribute the excess thickness of the weld and thus to reduce the thickness of the sheet by 5 to 20%, but

without eliminating it entirely.

  From a metallurgical point of view, the burnishing operation slightly hardens the metal to the right of the welded zone and makes it possible to significantly minimize the phenomenon of heterogeneity of the structure of the continuous strip,

  but the problem posed remains unresolved.

  Welding the tail of the first coil with the head of the second coil can also be

sparking.

  However, flash welding also results in metal thickening at the joint plane which it is necessary to grind before subjecting the continuous strip to subsequent treatments and before winding this continuous strip in the form of a coil. The object of the present invention is to avoid these drawbacks by proposing a joining and welding installation by means of a laser beam of two coils of metal strips, which makes it possible to obtain a welded zone having no excess thickness relative to the initial thickness of the strip and to obtain a continuous strip having no heterogeneity of structure so as to eliminate the risks of breakage of

  said strip during subsequent treatments.

  The invention therefore relates to an installation

  splicing and welding by means of a laser beam of two coils of metal strips to form a continuous metal strip, characterized in that it comprises: - means for unwinding and winding the coils, - an accumulator system the strip of the first reel, - means for detecting the tail of the first reel and the head of the second reel, - means for shearing the tail of the first reel and the head of the second reel, - means for guiding and supporting the metal strips of the coils, - a set for positioning and holding the edges to be welded of the tail of the first coil and of the head of the second coil against each other and in the laser beam axis, - and a laser beam welding assembly that can be moved along the joint plane formed by the

welding edges of said coils.

  According to another characteristic of the invention

  tion, the assembly for positioning and holding the edges to be welded comprises: - means for positioning the tail of the first coil according to a horizontal reference plane, - means for positioning the edge to be welded of the tail of the first coil in the axis of the laser beam, - means for holding the weld edge of the tail of the first coil in the axis of the laser beam, - means for clamping the tail of the first coil, - means for positioning of the head of the second coil along said horizontal plane, - means for holding the welding edge of the head of the second coil against the welding edge of the tail of the first coil, - means for tightening the head of the second coil, - and means of lateral pressurization

  edges to be welded strips of the two coils.

  The characteristics and advantages of the

  vention will appear during the description that goes

  follow, given only by way of example and made with reference to the appended drawings, in which: - FIG. 1 is a schematic view of an installation, according to the invention, of splicing and welding by means of a laser beam of two coils of metal strips, - FIG. 2 is a diagrammatic cross-sectional view, on a larger scale, of the assembly and positioning assembly for the edges to be welded of the two coils, in which the clamping means are in the raised position, FIG. 3 is a schematic sectional view along line 3-3 of FIG. 2, - Fig. 4 is a diagrammatic cross-sectional view, on a larger scale, of the assembly and positioning assembly of the edges to be welded of the two coils, in which the clamping means are in the closed position, - Figs. 5 to 8 are schematic views showing the different stages of splicing and

  welding of the welding edges of the two coils.

  After the cold rolling operation, the metal strips are wound in the form of coils and these coils are butted and welded two to

  two in an installation according to the invention.

  In the embodiment described below

  afterwards, the installation according to the invention intended for splicing and welding by means of a laser beam of two coils 1 and 2 of metal bands comprises, with respect to the direction of travel of the bands of the two coils 1 and 2 and as shown in Fig. 1: - means 3 for successively unwinding the strips of the two reels, - means 4 for detecting the tail 1a of the first reel 1 and of the head 2a of the second reel 2, - means 5 for shearing the tail the first coil 1 and the head 2a of the second coil 2, - a first means 6a for guiding and supporting the metal strips of the coils 1 and 2, - a set 10 for positioning and holding the edges to be welded the tail 1a of the first coil 1 and the head 2a of the second coil 2 against each other and in the axis of a laser beam, - a welding assembly 11 by laser beam displaceable along the joint plane formed by the welding edges of the coils 1 and 2, - a second means 6b for guiding and supporting the metal strips of the coils 1 and 2, an accumulator system 7 of the strip of the first coil 1, - one or more stations 8 of processing of the strips of the coils 1 and 2, for example for making a homogenization or stripping or coating, and finally means 9 for winding the

strip of the first reel 1.

  The shearing means 5 are formed by a conventional shear controlled by the detection means 4 and intended to successively cut the tail 1a of the first coil 1 and the head 2a of the second

coil 2.

  Alternatively, the shear means 5

  lage can be formed by two shears controlled by means of detection, on the one hand, of the tail 1a of the first coil 1 and, on the other hand, of the head 2a

of the second coil 2.

  In this case, a first shear is arranged, relative to the direction of travel of the metal strips, upstream of the assembly 10 for positioning and holding the edges to be welded and is intended to cut the head 2a of the second coil 2 and a second shear is disposed downstream of the assembly 10 for positioning and holding the edges to be welded and is

  intended to cut the tail of the first coil 1.

  The detection means 4 are constituted by

  example by at least one photocell.

  The first means 6a for guiding and supporting the metal strips is formed by at least one series of horizontal rollers, each comprising two lower rollers 60a, 62a and an upper roller 61a between

  which circulate the metal bands.

  The upper roller 61a is disposed between the lower rollers, respectively 60a and 62a, and the three rollers 60a, 61a and 62a are simultaneously movable vertically by suitable means not shown. The second means 6b for guiding and supporting the metal strips is also formed by at least one series of horizontal rollers, each comprising two lower rollers 60b and 62b and an upper roller 61b. The upper roller 61b is arranged between the lower rollers 60b and 62b and the three rollers

  b, 61b and 62b are vertically movable.

  According to a first embodiment, the rollers 60b, 61b and 62b can be moved horizontally in the direction opposite to the direction of travel of the metal strips. According to a second embodiment, the rollers 60b, 61b and 62b can be driven in the opposite direction relative to the direction of travel of the metal strips. Conventionally, the accumulator system 7 of the strip of the first reel 1 comprises a plurality of rollers 71 movable vertically and a

plurality of fixed rollers 72.

  The strip enters the accumulator system at one end, is wound alternately around the rollers 71 and 72 and exits from said accumulator system

by the other end.

  When the strip moves upstream of the accumulator faster than downstream, the length of the strip inside the accumulator increases, the movable rollers 71 then deviate from the fixed rollers

  72, which keeps the strip tight.

  Conversely, when the strip moves upstream of the accumulator more slowly than downstream, the length of the strip in the accumulator decreases and the movable rollers 71 approach the fixed rollers 72 without significant tensions appearing in

said strip.

  The assembly 10 for positioning and holding the edges to be welded of the tail 1a of the first coil 1 and of the head 2a of the second coil 2 against each other and in the axis of the laser beam 11 comprises: means 12 for guiding the metal strips at the entrance to said assembly, - means 20 for positioning the tail 1a of the first coil 1 along a horizontal reference plane, - means 30 for positioning the edge to be welded of the tail 1a the first coil 1 in the axis of the laser beam 11, - means 40 for holding the welding edge of the tail 1a of the first coil 1 in the axis of the laser beam 11, - means 50 for tightening the tail the of the first coil 1, - means 80 for positioning the head 2a of the second coil 2 along said horizontal reference plane, - means 90 for holding the edge to be welded of the head 2a of the second coil 2 against the weld edge of the tail of the first coil 1, - of s means 100 for clamping the head 2a of the second coil 2, - and means, respectively 110 and 120, for pressurizing the edges to be welded sideways

strips of the two coils 1 and 2.

  The means 20 for positioning the tail 1a of the first coil 1 are formed by at least one lower shoe 21 extending parallel to the joint plane of the edges to be welded of the tail 1a of the first

  coil 1 and head 2a of the second coil 2.

  This lower shoe 21 forms a continuous contact surface with the lower face of the tail 1a of the first coil 1 and is mounted to be moved on a support table 22, perpendicular to the joint plane.

said edges to be welded.

  This lower shoe 21 has two pins 23

  protruding from its lower surface.

  Each pin 23 enters a slot 24 formed in the support table 22 so as to guide the lower shoe 21 during its transverse movement relative to the joint plane of the edges to be welded. The means 30 for positioning the edge to be welded of the tail 1a of the first coil 1 are formed

  by a longitudinal and retractable stop 31.

  To this end, the stop 31 is connected to a mechanism 32 for vertical displacement of said stop 31 and is arranged vertically so that the joint plane passing through its lateral face located opposite the lower shoe 20 is coincident with the axis of the beam. laser 11. The mechanism 32 for vertical displacement of the

  stop 31 can be constituted by an eccentric mechanism

  than or by double acting cylinders.

  The means 40 for holding the weld edge of the tail 1a of the first coil 1 in the axis of the laser beam 11 are formed by at least one upper shoe 41 movable vertically and extending

  parallel to the joint plane of the edges to be welded.

  This upper shoe 41 forms a continuous contact surface with the upper face of the tail 1a of the first coil 1 and is arranged opposite the shoe.

lower 20.

  The lower shoe 20 and / or the upper shoe

  laughing 41 can be replaced by several juxtaposed pads forming substantially continuous surfaces

  of contact with the tail la of the first coil 1.

  The means 50 for clamping the tail 1a of the first coil 1 are formed by at least one jack 51 intended to exert on the upper shoe 41 a vertical pressure to clamp said tail 1a of the first

  coil 1 between this upper shoe 41 and the lower shoe

laughing 21.

  li The cylinder 51 comprises a body 52 supported by a beam 53 extending parallel to the upper shoe 41 and a rod 54 vertically movable and integral

of said upper shoe 41.

  The assembly formed by the upper shoe

  41, the jack 51 and the beam 53 is vertically movable

  wedging to lift said upper shoe 41 and provide sufficient space between the upper shoe 41 and the lower shoe 21 for the passage of the strips of

coils 1 and 2.

  The vertical displacement of this assembly is ensured by suitable members, not shown, such as

  for example by a rack system or a jack.

  The means 80 for positioning the head 2a of the second coil 2 are formed by at least one fixed lower shoe 81, bearing on a support table 82, and extending parallel to the joint plane of the

edges to be welded.

  The lower shoe 81 forms a continuous contact surface with the lower face of the head 2a of

the second coil 2.

  The lower shoe 81 is supported by its lateral face 81a opposite to that facing the joint plane of the edges to be welded, on at least one stop member.

  83 secured to the support table 82.

  The means 90 for holding the weld edge of the head 2a of the second coil 2 against the weld edge of the tail 1a of the first coil 1 are formed

  by at least one upper shoe 91 extending parallel-

  at the joint plane of the edges to be welded.

  This upper shoe 91 forms a continuous contact surface with the upper face of the head 2a of the second coil 2 and is arranged opposite the shoe.

lower 81.

  The lower shoe 81 and the upper shoe 91 can be replaced by several juxtaposed shoes forming substantially continuous contact surfaces

  with the head 2a of the second coil 2.

  The means 100 for clamping the head 2a of the second coil 2 are formed by at least one cylinder 101 intended to exert on the upper shoe 91 a vertical pressure to tighten said head 2a of the second coil 2 between this upper shoe 91 and the skate

lower 81.

  The jack 101 comprises a body 102 supported by a beam 103 extending parallel to the upper shoe 91 and a rod 104 movable vertically and

  secured to said upper shoe 91.

  The assembly formed by the upper shoe

  91, the jack 101 and the beam 103 is movable ver-

  tically from a height sufficient to lift the upper shoe 91 and provide between this upper shoe 91 and the lower shoe 81 a space allowing the

passage of the bands.

  The vertical movement of this assembly is ensured for example by a rack mechanism or a

  cylinder or any other suitable mechanism.

  The upper shoe 91 is supported by its lateral face 91a opposite that opposite the joint plane of the edges to be welded, on at least one stop member.

92 secured to the beam 103.

  The stop members 83 and 92 prevent sliding, respectively of the lower shoe 81 and of the upper shoe 91, when a lateral pressure is exerted on the edges to be welded of the tail 1a of the first coil 1 and of the head 2a of the second reel

  2, as will be seen later.

  The means 110 and 120 for lateral pressure of the edges to be welded of the two coils 1 and 2 are formed, on the one hand, by at least one first jack 111 associated with the lower pad 21 and, on the other hand, by at

  at least a second cylinder 121 associated with the upper shoe 41.

  The cylinder 111 comprises a rod 112 displaced

  ble horizontally and connected to the lower shoe 21 by at least one pin 113 which passes through the support table 22. In the example shown in the figures,

  two jacks 111 are associated with the lower shoe 21.

  The jack 121 is supported by the beam 53 and has a rod 122 which can be moved horizontally which acts on the upper shoe 41 via the body

52 and the rod 54 of the jack 51.

  In the example shown in the figures,

  two jacks 121 are associated with the upper shoe 41.

  Cylinders 111 and 121 are ordered in

  synchronization and are intended to exercise on, respec-

  the lower shoe 21 and the upper shoe 41, a pressure determined and directed in a direction

  perpendicular to the joint plane of the edges to be welded.

  The installation according to the invention works

as follows.

  First, the first coil is placed

  on the unwinding means 3 and the strip is unwound.

  This tape passes through means of ci-

  projection 5 between the rollers 60a, 60b and 60c, in the assembly 10 for positioning and holding the edges to be welded, between the rollers 60b, 61b and 62b, in the accumulation system 7, in the treatment station 8 and is finally wound up in the form of a coil 1 by

the winding device 9.

  Following the unwinding of the first reel, a second reel 2 is unwound and follows the same route. To allow the strips to pass through the assembly 10 for positioning and holding the edges to be welded, the operator has placed the guide means 6a and 6b in the high position and has raised the upper runners

  41 and 91, as shown in Figs. 1 and 2.

  During the travel of the strip of the first reel 1, the detection means 4 detect the tail 1a of the strip of this first reel 1 which causes the running of the portion of the strip located

  between the shearing means 5 and the accumulator system

  lation 7, the portion of the strip located downstream of this accumulation system 7 continuing to move

  normally using the length of the accumulated tape

  linked in said accumulation system.

  The detection means 4 control the shearing means 5 which has the effect of cutting the tail 2a of the first coil 2, as shown in the

Fig. 5.

  Then, the portion of the strip of the first coil 1 located upstream of the accumulator system 7 advances again and the operator controls the rise of

the retractable stop 31.

  After this sequence, the operator controls the descent of the means 6b for guiding and supporting the

  tail of the first coil 1, as well as the

  ment of these guide and support means in the direction opposite to the direction of travel of the strip of the first coil 1 so that the edge to be welded of the tail 1a of this first coil 1 is applied to the stop 31 in order to position said edge to be welded

in the axis of the laser beam 11.

  According to a variant, the means 6b for guiding and supporting the tail 1a of the first coil can be driven in opposite directions so that the edge to be welded of the tail 1a of this first coil 1 comes

apply to stop 31.

  The operator also controls the descent of the assembly constituted by the upper shoe 41, the jack 51 and the beam 53 to tighten the tail of the first

  coil 1 between the lower shoe 21 and the upper shoe

  laugh 41 and maintain the weld edge of the tail 1a of said first coil 1 in the axis of the laser beam 11, as shown in FIG. 6. Simultaneously, the detection means 4

  detect the head 2a of the second coil 2 and com-

  instruct the stop of the strip of this second coil 2 and the shearing means 5 to cut the head 2a of

said second coil 2.

  After the head 2a of the second coil 2 has passed through the guide and support means 6a, the operator controls the descent of these guide and support means 6a to bring the edge to be welded from the head 2a of the second coil 2 against the weld edge of the tail of the first coil 1, after having

  retracted the stop 31, as shown in FIG. 7.

  As soon as the head 2a of the second coil 2 comes into contact with the tail 1a of the first coil 1, the operator controls the descent of the upper shoe

91 (Figs. 4 and 7).

  The jacks 51 and 101 are put under pressure and act on the upper shoes, respectively 41 and 91, so as to clamp, on the one hand, the tail 1a of the first coil 1 between the upper shoe 41 and the lower shoe 21 and , on the other hand, the head 2a of the second coil between the upper shoe 91 and the lower shoe 81 and to maintain the edges to be welded in the axis of the

laser beam 11.

  The clamping pressure exerted by the upper pads 41 and 91 is adjustable and can be determined according to the characteristics and / or the thickness of the

  metal bands constituting the coils 1 and 2.

  To ensure a minimum of clearance between the edges to be welded, the operator controls the pressurization

cylinders 111 and 121.

  The rod 112 of the jack 111 acts through the

  median of the pin 113, on the lower shoe 21 which moves perpendicular to the joint plane of the edges to be welded and the rod 112 of the jack 121 acts, via the jack 51, on the upper shoe 41 which moves perpendicularly at the edge joint plane

welding.

  Thus, the displacement perpendicular to the joint plane of the edges to be welded of the lower shoe 21 and of the upper shoe 41 exerts on the edges to be welded.

lateral pressure.

  The lateral displacement of the lower shoe 81 and of the lower shoe 91 is prevented by the rollers,

83 and 92 respectively.

  The lateral pressure exerted by the jacks 111 and 121 is adjustable and can be determined according to the characteristics and / or the thickness of the metal strips so as to avoid buckling of

  this and an overlap at the joint plane.

  Then, the operator controls the movement of the welding assembly in such a way that the laser beam 11 moves above the joint plane and ensures the welding of the edges to be welded of the tail 1a of the first coil 1 with the head 2a of the second coil 2. During the joining and welding of the edges to be welded, the portion of the strip of the first coil 1 located downstream of the accumulator system 7 takes place

  normally and the length of the strip in the accumulator-

tor decreases.

  After welding the edges to be welded, the ope-

  rator controls the rise, on the one hand, of the beams 53 and 103 which has the effect of lifting the upper runners 41 and 91 and, on the other hand, means 6a and 6b for guiding and supporting the metal strips so to prevent these metal bands from being in contact with the lower pads 21 and 81 during the running of these bands. The advantages of the invention according to the

present invention are multiple.

  In fact, the installation according to the invention makes it possible to carry out the splicing and the welding of two coils without disturbing the processing stations located downstream of this installation and to avoid a break at the junction between the two spliced coils, by welding the edges with a laser beam.

  Finally, the installation according to the invention makes it possible to produce a weld of perfect quality while avoiding excess thicknesses at the level of the welded zone thus avoiding marking of the strip at the time of

tape winding.

Claims (23)

  1. Joining and welding installation by means of a laser beam (11) of two coils (12) of metal strips to form a continuous metal strip, characterized in that it comprises:   - unwinding (3) and winding means   reel (9) of the coils (1, 2), - an accumulator system (7) of the strip of the first reel (1), - means (4) for detecting the tail (la) of the first reel (1 ) and the head (2a) of the second coil (2), means (5) for shearing the tail (la) of the first coil (1) and the head (2a) of the second coil (2) , - means (6a, 6b) for guiding and supporting the metal strips of the coils (1, 2), - an assembly (10) for positioning and holding the edges to be welded of the tail (la) of the first coil (1) and the head (2a) of the second coil (2) against each other and in the axis of the laser beam (11), - and a welding assembly by laser beam displaceable along the joint plane formed by the   welding edges of said coils (1, 2).   2. Installation according to claim 1, characterized in that the shearing means (5) are formed by a shear arranged, relative to the direction of travel of the metal strips, upstream of the assembly (10) for positioning and holding edges to be welded, said shears being controlled by said detection means (4) and intended to cut successively the tail (la) of the first coil (1) and the head (2a) of the second coil (2).   3. Installation according to claim 1, characterized in that the shearing means (5) are formed by two shears controlled by the detection means (4), the first shear being arranged, relative to the direction of travel of the metal strips, upstream of the assembly (10) for positioning and holding the edges to be welded and intended to cut the head (2a) of the second coil (2) and the second shear being disposed, relative to the direction of travel of the metal strips , downstream of the assembly (10) for positioning and holding the edges to be welded and intended to cut   the tail (la) of the first coil (1).   4. Installation according to claim 1, characterized in that the means for guiding and supporting the metal strips are formed by at least two series (6a, 6b) of horizontal rollers movable vertically and each comprising two lower rollers (60a, 62a and 60b, 62b) and an upper roller (61a and 61b), between which the metal strips circulate, the upper roller (61a and 61b) of each series (6a and 6b) being arranged between the rollers lower (60a, 62a and 60b, 62b).   5. Installation according to claims 1 and   4, characterized in that at least a first series (6a) of rollers is disposed upstream of the assembly (10) for positioning and holding the edges to be welded by   relation to the direction of travel of the metal strips.   6. Installation according to claims 1 and   4, characterized in that at least a second series (6b) of rollers is disposed downstream of the assembly (10) for positioning and holding the edges to be welded by   relation to the direction of travel of the metal strips.   7. Installation according to claims 4 and   6 characterized in that said second series (6b) of   rollers can be moved horizontally in the direction   opposite tion in the direction of travel of the metal strips   ques. 8. Installation according to claim 1, characterized in that the assembly (10) for positioning and holding the edges to be welded comprises: - means (20) for positioning the tail (la) of the first coil (1) along a horizontal reference plane, - means (30) for positioning the edges to be welded of the tail (la) of the first coil (1) in the axis of the laser beam (11), - means (40) of holding the weld edge of the tail (la) of the first coil (1) in the axis of the laser beam (11), - means (50) for clamping the tail (la) of the first coil (1) , - means (80) for positioning the head (2a) of the second coil (2) along said horizontal plane, - means (90) for holding the edge to be welded of the head (2a) of the second coil ( 2) against the weld edge of the tail (la) of the first coil (1), - means (100) for clamping the head (2a) of the second coil (2), - and means (110, 120) lateral pressurization e of the edges to be welded strips of the two coils (1, 2).   9. Installation according to claim 8, characterized in that the means (20) for positioning the tail (la) of the first coil (1) are formed   by at least one lower shoe (21) extending parallel   Lement to the joint plane of the edges to be welded, said lower shoe (21) forming a continuous contact surface with the underside of the tail (la) of the first coil (1) and being mounted movable on a support table (22) , perpendicular to the joint plane said edges to be welded.   10. Installation according to claims 8   and 9, characterized in that the means (30) for positioning   tction of the edge to be welded of the tail (la) of the first coil (1) are formed by a stop (31) longitudinal and retractable, arranged vertically so that the plane passing through its side face located opposite the lower shoe (21) , or confused with the axis of the laser beam (11).   11. Installation according to claims 8   and 9, characterized in that the means (40) for holding the weld edge of the tail (la) of the first coil (1) in the axis of the laser beam (11) are formed by at least one upper shoe ( 41) movable vertically and extending parallel to the joint plane of the edges to be welded, said upper shoe (41) forming a continuous contact surface with the upper face of the tail (la) of the first coil (1) and being arranged in look of said lower shoe (21).   12. Installation according to claims 8,   9 and 11, characterized in that the means (50) for tightening the tail (la) of the first coil (1) are formed by at least one jack (51) intended to exert pressure on the upper shoe (41) vertical to clamp said tail (la) of the first coil (1) between   this upper shoe (41) and the lower shoe (21).   13. Installation according to claim 11, characterized in that said cylinder (51) comprises a body   (52) supported by a beam (53) extending parallel-   ment to the upper shoe (41) and a movable rod (54)   vertically and integral with said upper shoe (41).   14. Installation according to claims 11   to 13, characterized in that the assembly constituted by said upper shoe (41), said cylinder (51) and said   beam (53) is vertically movable.   15. Installation according to claim 8, characterized in that the means (80) for positioning the head (2a) of the second coil (2) are formed by at least one lower pad (81) fixed, resting on a table support (82) and extending parallel to the joint plane of the edges to be welded, said lower shoe (81) forming a continuous contact surface with the face   bottom of the head (2a) of the second coil (2).   16. Installation according to claim 15, characterized in that the lower shoe (81) is supported by its lateral face (81a) opposite to that facing the joint plane to be welded, on at least one member   stop (83) integral with the support table (89).   17. Installation according to claims 8   and 15, characterized in that the means (90) for holding the weld edge of the head (2a) of the second coil (2) against the weld edge of the tail (la) of the first coil (1) are formed by at least one upper shoe (91) extending parallel to the joint plane of the edges to be welded, said upper shoe (91) forming a continuous contact surface with the upper face of the head (2a) of the second coil ( 2) and being   arranged opposite the lower shoe (81).   18. Installation according to claim 17, characterized in that the means (100) for clamping the head (2a) of the second coil (2) are formed by at least one jack (101) intended to exert on the upper shoe ( 91) vertical pressure to clamp the head (2a) of the second coil (2) between this upper shoe (91) and the lower shoe (81).   19. Installation according to claim 18, characterized in that said cylinder (101) comprises a body (102) supported by a beam (103) extending parallel to the upper shoe (91) and a rod (104) movable vertically and integral said skate upper (91).   20. Installation according to claims 17   19, characterized in that the assembly constituted by said upper shoe (91), said cylinder (101) and said   beam (103) is vertically movable.   21. Installation according to claims 17   and 18, characterized in that the upper shoe (91) is supported by its lateral face (91a) opposite to that facing the joint plane of the edges to be welded, on at least   a stop member (92) integral with said beam (103).   22. Installation according to any one of   claims 8 to 21, characterized in that the means   (110, 120) for lateral pressure of the edges to be welded of the two coils (1, 2) are formed, on the one hand, by at least one first jack (111) associated with the lower pad (21) for positioning the tail (la) of the first reel (1) and, on the other hand, by at least one second jack (121) associated with the upper shoe (41) for holding the tail (la) of said first reel (1), said cylinders (111, 121) being intended to exert, respectively on the lower shoe (21) and on the upper shoe (41), a pressure directed in a direction perpendicular to the joint plane of the edges to solder.   23. Installation according to claim (22), characterized in that the jacks (111, 121) are ordered in synchronization.